I've just been going through this process of deciding on 12ZX7s for my DB659 and Brick. Here are my opinions

For NOS, get GE tubes for bass amps (maybe not best for audio, but have a great warm bottom, and good defined bass) ... the black plate 1950s are best, but too expensive; the grey plates are good; 5751 are good too and cheap ($15) but have a mu of only 70 versus 100 for the 12aX7. Amperex bugleboy and Mullard are good too, but expensive (too much). Forget the rest ... expecially Telefunken which is not good at all for bass.

For new tubes get the JJ's or the GT 12aX7-M (Mullard copy). The Chinese GT 12ax7C are average, and I would recommend against. The Russian GT 12ax7 R are awful ... variable quality, low output (mu around 50 it seems).

Spend your money on the V1 tube ... this is really where you will hear the difference ... and it is huge between tubes. Tubes define the sound of an amp ... so spend your money on the tubes if you've got a good amp. So perhaps get a GE black plate 1950s 12AX7 for the V1, and Chinese GT 12AX7 C for the rest of the signal triodes

Interesting thing about the GE 5751 grey plate is that this was originally (1950s) a premium tube which was supposed to have fewer production variances and better sound than the 12ax7 (at the expense of slightly less amplification). But the military ordered zillions of them in the 1970s and 1980s so there is a lot of NOS around, and the price is lower than the inferior 12ax7s. In the 1950s they were adding a third mica spacer, which stabilized the parts, and lowered microphonics. They cost cut to two spacers in the late 1970s. That said, I'm using the 1987 vintage 5751s in both my DB659 and Brick, and I can tap and wiggle the tubes without noticing any microphonics.

If you are cost conscious, I think the way to ration your NOS tubes is to use the stock GT 12zx7-C (Chinese) for all but the V1 tube, and put the NOS in the V1 which really does all the tone shaping in any preamp